GB2093953A

GB2093953A - Multiple control valve system

Info

Publication number: GB2093953A
Application number: GB8200325A
Authority: GB
Original assignee: Toshiba Machine Co Ltd
Current assignee: Shibaura Machine Co Ltd
Priority date: 1981-01-13
Filing date: 1982-01-06
Publication date: 1982-09-08
Also published as: JPS642807B2; US4557291A; FR2497912B1; JPS57116917A; DE3200419A1; GB2093953B; DE3200419C2; FR2497912A1

Description

1 GB 2 093 953 A 1

SPECIFICATION Multiple control valve system

Background of the invention

This invention relates to an improvement of a multiple control valve system which comprises a 70 multiple control valve and valve means attached thereto.

Various types or forms of multiple control valves have been widely used and known in the art of this field, and atypical example of these valves will be described hereunder in conjunction with Fig. 1. Fig. 1 shows a multiple control valve 11 having a plurality of spools for changing flow direction of an oil passing through the multiple control valve in which a valve body 12 is provided with an iniet chamber 13 into which a pressurized oil is supplied from an external oil source through a pump 14. The pressurized oil is discharged, under an unloaded condition, into a drain tank 19 through a by-pass passage 18 formed at the 85 central portions of the valve body 12 to be opened by spools 15 and 17 when the spools 15 and 17 occupy their neutral positions as shown in Fig. 1. The pressurized oil is also supplied to the spools 15 and 17 in communication with side passages 20 and 21 connected to and extending from the inlet chamber 13.

When a spool 16 is moved rightwardly as viewed in Fig. 1, the by-pass passage 18 is closed by an enlarged central portion and outer surface of the spool 16 and the side passage 20 comes to communicate with a hole 22 provided for the spool 16, whereby the pressurized oil is guided to one hydraulic chamber located on one side of an actuator, not shown, which hydraulically operates through an axial hole, not shown, of the spool 16, - a hole 23, and a cylinder port 24. A pressurized oil in the other hydraulic chamber on the other side of the actuator flows into the tank 19 through a cylinder port 25, holes 26, 27, and a return 105 passage 28.

In a case where a multiple control valve such as shown in Fig. 1 is incorporated in a civil machine, for example a bulldozer, the spools 15 and 17 of the control valve 11 are operatively connected to a travelling motor and actuators of a bucket and a boom, respectively. A recent civil machine is often provided with a hydraulic breaker as an attachment member in addition to the travelling motor and the actuators of the bucket and the boom ' One example of such a multiple control valve is shown in Fig. 2 in which like reference numerals are applied to elements corresponding to those shown in Fig. 1 or a capital letter "A" is added thereto, and the multiple control valve provided with an additional valve is referred to as a multiple control valve system hereunder.

A multiple control valve 11 A shown in Fig. 2 is different from that 11 shown in Fig. 1 in that an inlet chamber 1 3A of a valve body 1 2A does not communicate with side passages 20A and 21 A, which are connected to a pump 14 through conduits 31 and 33. The valve body 35 of a valve 34 (called an attachment valve 34 hereinbelow) attached to the valve 11 A is provided with an inlet chamber 36 which is connected to a drain tank 19 through the pump 14. When the spool 37 of the attachment valve 34 occupies its neutral position as shown in Fig. 2, pressurized oil supplied to the inlet chamber 36 flows into the inlet chamber 13A of the multiple control valve 11 A through a by-pass passage 38, a central portion of the spool 37, and a pipe 39 which is communicated with the inlet chamber 13A, and then the pressurized oil is discharged into the tank 19 where the spools 15 and 17 occupy their neutral positions.

In the meantime, when the spool 16 of the valve 1 1A is moved rightwardly as viewed in Fig. 2, as described in connection with Fig. 1, the bypass passage 18 is closed and the pressurized oil entered into the passage 20A is fed into one hydraulic chamber located on one side of an external actuator, not shown, which hydraulically operates, through holes 22, 23 and the cylinder port 24. The pressurized oil in the other hydraulic chamber on the other side of the actuator is discharged into the tank 19 through the cylinder port 25, holes 26, 27, and the passage 28. When the spool 37 of the attachment valve 34 is moved rightwardly, the pressurized oil in the inlet chamber 36 is fed to one hydraulic chamber located on one side of an actuator, not shown, which operates hydraulically, through a side passage 40, holes 41, 42, 43, and a cylinder port 44 and the pressurized oil in the other hydraulic chamber on the other side of the actuator is discharged into the tank 19 through a cylinder port 45, holes 46, 47, 48, and a return passage 49.

With the multiple control valve system shown in Fig. 2, the valve body 12A of the multiple control valve 1 2A is different from the valve body 12 of the valve 11 in their constructions because the conduits 31 and 32 are connected to the valve body 12A, so that it is impossible to apply a usual multiple control valve as shown in Fig. 1 as it is to a multiple control valve system as shown in Fig. 2 and it is obliged to manufacture independently the valve body 1 2A without utilizing the valve body 12. This inconvenience results in the increase in the manufacturing cost as well as manufacturing steps.

Summary of the invention

An object of this invention is to provide an improved multiple control valve system capable of utilizing an ordinary multiple control valve and an additional valve to be attached to the multiple control valve without using conduits connecting the valve body of the multiple control valve and an oil source, the use of such conduits making impossible to utilize an ordinary multiple control valve as it is.

According to this invention, there is provided a multiple control valve system of the type comprising a multiple control valve having an oil inlet chamber connected to an external 2 GB 2 093 953 A 2 pressurized oil source, oil passages connected to the oil inlet chamber, and a plurality of spools for 65 changing overflow direction of the pressurized oil passing through the oil passages and an additional attachment valve operatively connected to the multiple control valve and having an oil inlet chamber connected to the external pressurized oil source, oil passages connected to the oil inlet chamber of said attachment valve, and a spool for changing over flow direction of the pressurized oil passing through the oil passages of the attachment valve, and the multiple control valve system further comprises a logic valve oil-tightly attached to the multiple control valve so as to be communicated with the oil passages formed in the multiple control valve and a change-over valve operatively connected to the spool of said attachment valve so as to be communicated with the oil passages of the attachment valve and connected to the logic valve through a conduit.

Brief description of the drawings

In the accompanying drawings:

Fig. 1 shows a longitudinal section of a known type multiple control valve; Fig. 2 shows a longitudinal section of a known type multiple control valve system; Fig. 3 shows a longitudinal section of an embodiment of a multiple control valve system according to this invention; and Fig. 4 shows a longitudinal section of another 95 embodiment of a multiple control valve system according to this invention.

Description of the preferred embodiments

Fig. 3 shows one embodiment of a multiple control valve system according to this invention, in which like reference numerals are applied to elements corresponding to those shown in Figs. 1 and 2 and the corresponding elements shown in Fig. 3 operate in substantially the same manner as described with reference to Fig. 2.

A logic valve 51 which controls a loaded or unloaded condition due to the pressurized oil passing through the by-pass passage 18 or the return passage 28 is mounted on the downstream 110 side of the by-pass passage 18 in the multiple control valve 11. The logic valve 51 comprises a hollow valve body 52 which is water-tightly attached to the valve body 12 and i spool 54 attached to the valve body 35, and a valve member 64 secured to the spool. 37 through a joint member 63 is inserted into the cylindrical member 62 which is provided with a pilot port 66 surrounding a land portion 65 of the valve member 64 and communicated with the conduit 58. Thus, the pilot change-over valve 61 and the logic valve 51 are operatively connected to each other through the conduit 58. A passage 67 which is connected to the return passage 49 of the valve body 35 is formed on both sides of the pilot port 66.

In the multiple control valve system described above, the inlet chambers 13 and 36 of the multiple control valve 11 and the attachment valve 34 are connected respectively to the pump 14 through the conduits 70 and 69 which are parallelly arranged.

The multiple control valve system according to this invention operates as follows.

When the spool 37 of the attachment valve 34 and the spools 15 and 17 of the multiple control valve 11 are positioned in their neutral positions, pressurized oil is supplied from the tank 19 into the inlet chamber 36 of the attachment valve through the conduit 69 and then flows into the by-pass passages 38 which are blocked by the plug 68. In the meantime, the pressurized oil supplied from the tank 19 enters into the inlet chamber 13 of the multiple control valve 11 through the conduit 70 and then flows into the by-pass passage 18. At this time, the pilot chamber 57 of the logic valve 51 is connected to the tank 19 through the conduit 58, the passage 67 of the pilot change-over valve 6 1, and the return passage 49 of the attachment valve 34, so that the spoof 54 of the logic valve 51 is lowered by the pressure applied on the upper surface of the spoof 54 against the urging force of the spring 56, whereby the by-pass passage 18 is communicated with the return passage 28 and the pressurized oil is discharged into the tank 19.

When the spool 16 of the multiple control valve 11 is moved rightwardiy while maintaining the spool 37 of the attachment valve 34 at its neutral position, the bypass passage 18 is closed and the pressurized oil enters into one hydraulic chamber of the external actuator, not shown, through the side passage 20, the holes 22, 23, and the cylinder port 24. The pressurized. oil in the other hydraulic chamber of the actuator flows into which is to be inserted into the valve body 52 and 115 the tank 19 through the cylinder port 25, the is provided with a hole 53 at the front end. The spool 54 is always urged upwardly as viewed in Fig. 3 by a spring 56 having one end engaging a plug 55 which is inserted into the lower end of the hollow valve body 52. A pilot chamber 57 is formed within the valve body 52 between the plug 55 and the lower end of the spool 54 and the pilot chamber 57 is communicated with a conduit 58 through the plug 55.

A pilot change-over valve 61 is attached to one 125 end (righthand end in Fig. 3) of the spool 37 of the attachment valve 34. The change-over valve 61 has a cylindrical member 62 water-tightly 7 holes 26, 27, and the return passage 28. When the spool 37 of the valve 34 is moved rightwardly, the valve member 64 of the change-over valve 61 attached thereto also moves rightwardly and the communication between the pilot port 66 and the passage 67 is shut out. Namely, because the connection between the pilot chamber 57 of the logic valve 51 and the tank 19 is shut out, the pressurized oil passing through the hole 53 of the spool 54 acts on the downstream portion of the spool 54. The cross-sectional area of the upper portion of the spool 54 is larger than that of the lower portion thereof, so that the spool 54 rises 3 GB 2 093 953 A 3 and shuts out the communication between the by-pass passage 18 and the return passage 28, whereby the hydraulic pressure in the inlet chamber of the attachment valve 34 rises, and the pressurized oil in the chamber 36 flows into one hydraulic chamber of an external actuator, not shown, through the side passage 40, the holes 41, 42, 43, and the cylinder port 44. At this time, the pressurized oil in the other hydraulic chamber of the actuator flows into the tank 19 through the cylinder port 45, the holes 46, 47, 48, and the return passage 49.

Although, in the embodiment of this invention described above, the pressurized oil in the tank 19 is parallelly supplied by the operation of the pump 14 into the attachment valve 34 and the multiple cont rol valve 11 respectively through the conduits 69 and 70, the pressurized oil can be supplied thereinto through conduits 69A and 39A which interconnect the attachment valve 34 and the multiple control valve 11 in the other embodiment shown in the Fig. 4. With the embodiment shown in Fig. 4, the pressurized oil flows from the tank 19 into the multiple control !alve 11 through the conduit 69A, the attachment valve 34, and the conduit 39A in substantially the same manner as that described with reference to Fig. 2.

According to the multiple control valve system of this invention, where the attachment valve 34 is in its neutral position, the logic valve 51 secured to the downstream portion of the by-pass passage 18 of the usual multiple control valve 11 is opened thereby to maintain the unloaded condition of the multiple control valve assembly.

On the other hand, in a case where the attachment valve 34 is in its operative position, the pilot change-over valve 61 connected to the spool 37 of the attachment valve 34 operates so as to shut out the logic valve 51 to maintain the loaded condition and to actuate an actuator connected to cylinder ports 44, 45 of the attachment valve 34.

The multiple control valve systems of this 90 invention can utilize valve bodies of usual multiple control valves without the necessity of newly manufacturing them and using additional conduits or pipes, whereby the multiple control valve system is economically manufactured and the manufacturing steps can be reduced.

Claims

1. A multiple control valve system of the type comprising a multiple control valve having an oil inlet chamber connected to an external pressurized oil source, oil passages connected to said oil inlet chamber, and a plurality of spools for changing overflow direction of the pressurized oil passing through said oil passages and an additional attachment valve operatively connected to said multiple control valve and having an oil inlet chamber connected to said external pressurized oil source, oil passages connected to said oil inlet chamber of said attachment valve, and a spool for changing over flow direction of the pressurized oil passing through said oil passages of said attachment valve, characterized in that said multiple control valve system further comprises a logic valve oiltightly attached to said multiple control valve so as to be communicated with said oil passages formed in said multiple control valve and a change-over valve operatively connected to said spool of said attachment valve so as to be communicated with said oil passages of said attachment valve and connected to said logic valve through a conduit.

2. The multiple control valve system according to claim 1 wherein the pressurized oil is parallelly supplied into said oil inlet chambers of said multiple control valve and attachment valve from said external _pressurized oil source through conduits, respectively.

3. The multiple control valve system according to claim 1 wherein the pressurized oil is supplied into said oil inlet chambers of said multiple control valve and attachment valve from said external pressurized oil source through a conduit connecting said oil source and said oil inlet chamber of said attachment valve, said oil passages formed therein, and a conduit connecting said last mentioned oil passages and said oil inlet chamber of said multiple control valve.

Printed for Her Majesty's Stationery Office by the Courier Press, Leamington Spa, 1982. Published by the Patent Office, 25 Southampton Buildings, London, WC2A 1 AY, from which copies may be obtained.